| 摘要 |
A hydrogen fuel cell power system having improved efficiency comprises a fuel cell, a source of hydrogen gas, a compressor for creating a pressurized air stream, and a liquid supply which is heated by waste heat form the power system and evaporates into the pressurized air stream to produce a pressurized air and steam mixture. The pressurized air/steam mixture, which is preferably used as the oxidant in the fuel cell, is combusted with fuel in a burner to produce a high-temperature steam-laden exhaust stream. The high-temperature steam-laden exhaust stream drives an expander to produce a power output, and a power take-off from the expander uses the expander power to, for instance, drive an electrical generator, or drive other system components.; The evaporation of liquid can take place external to the fuel cell, or can take place directly within the fuel cell, preferably using a cooling liquid that is directly injected into the fuel cell. The fuel cell power system advantageously uses the low-temperature waste heat of the fuel cell to evaporate liquid into the pressurized air, resulting in a steam/air mixture having a relatively large expansion potential. The systems and related methods of the invention are applicable to a wide range of fuel cell power systems, including a "pure" or "non-hybrid" fuel cell power system, powered by hydrogen from either an external source, such as a hydrogen storage tank, or from "direct" reforming of a fuel at the anode. The invention is also applicable to integrated or "hybridized" fuel cell power systems which contain a local fuel reformer.; In these systems, the fuel cell is powered by hydrogen-containing reformate generated by the reformer. |
